Methods and devices for cutting and abrading tissue

ABSTRACT

The present invention provides an atherectomy catheter which has a cutting element that is able to cut both soft tissue and hard tissue, and methods of cutting material from a blood vessel lumen using a rotating cutting element. The cutting element has a sharp cutting edge that surrounds a cup-shaped surface and at least one surface of abrasive material. The cup-shaped surface directs the cut material into a tissue chamber. The cutting edge and the cup-shaped surface together are well suited to cut and remove relatively soft tissue from the blood vessel. The abrasive material surface in combination with the cutting element is well suited to abrade and remove hard material from the blood vessel.

This application claims the benefit of U.S. Provisional PatentApplication No. 61/173,845, filed Apr. 29, 2009, entitled “Methods andDevices for Cutting/Abrading Tissue”, the contents of which are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to catheters used to remove material froma site in a body lumen. More particularly, this invention pertains tocutters capable of removing both soft and hard material from the site.

BACKGROUND OF THE INVENTION

Atherosclerosis is a progressive disease of the vascular system wherebyatheroma is deposited on the inner walls of blood vessels. Over timeatheromatous deposits can become large enough to reduce or occlude bloodflow through the vessels, leading to symptoms of low blood flow such aspain in the legs (on walking or at rest), skin ulcer, angina (at rest orexertional), and other symptoms. To treat this disease and improve orresolve these symptoms it is desirable to restore or improve blood flowthrough the vessel.

Various means are used to restore or improve blood flow throughatheromatous vessels. The atheroma deposits can be displaced bydiametrically expanding the vessel by inflating balloons, expandingstents, and other methods. However these methods undesirably tear andstretch the vessel, causing scar formation in a high percentage ofpatients. Such scar tissue (restenotic material), once formed, blocksflow in the vessel and often needs to be removed. The deposits can bepulverized using lasers and other methods. However pulverization aloneof atheromatous material allows microemboli to flow downstream and lodgein distal vascular beds, further compromising blood flow to the tissueaffected by the disease. Atherectomy catheters can be used to removeatheromatous deposits from the blood vessel and can present an idealsolution when the atheromatous debris removed from the vessel iscaptured and removed from the body.

One problem that occurs when removing material from a blood vessel isthat the material may be either soft or hard. Typically, restenotic scaris soft yet tough while atheroma varies in texture from soft with littlestructure, to soft yet fibrotic, to densely fibrotic (hard). Any or allof these restenotic or atheromatous tissues may be calcified and thecalcified tissues can be extremely hard. The hardness and toughnesscharacteristics of the material needing to be cut from the vessel mayvary along the length of the vessel, around the circumference of thevessel, or both. Further, the portion of the vessel to be treated can bequite extensive. For example, the portion of the vessel to be treatedcan extend over a vessel length of 200 mm or longer. As such, thecutting element of an atherectomy catheter should be able to cut bothhard tissue and soft tissue.

SUMMARY OF THE INVENTION

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; and a cutting element coupled to the rotatable shaft forrotating the shaft about a longitudinal axis, the cutting element havinga cup-shaped surface and a cutting edge, the cup-shaped surface beingconfigured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction, andthe cutting element having at least one abrasive surface. The inventionalso provides a method of removing material from a body lumen, themethod comprising: providing an atherectomy catheter, placing thecatheter in the body lumen; and moving the catheter in the body lumen tocontact the cutting element with the material in the body lumen.

The present invention provides an atherectomy catheter which has acutting element that is able to cut both soft tissue and hard tissue,and methods of cutting material from a blood vessel lumen using arotating cutting element. The cutting element has a sharp cutting edgethat surrounds a cup-shaped surface and at least one surface of abrasivematerial. The cup-shaped surface directs the cut material into a tissuechamber. The circumferential cutting edge and the cup-shaped surfacetogether are well suited to cut and remove relatively soft tissue fromthe blood vessel. The abrasive material surface in combination with thecutting element is well suited to abrade and remove hard material fromthe blood vessel.

These and other aspects of the invention will become apparent from thefollowing description of the preferred embodiments, drawings and claims.The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an isometric view of an atherectomy catheter.

FIG. 2 illustrates an isometric cross-sectional view of a portion of theatherectomy catheter illustrated in FIG. 1 with a cutting element in astored position.

FIG. 3 illustrates an isometric cross-sectional view of a portion of theatherectomy catheter illustrated in FIG. 1 with a cutting element in aworking position.

FIG. 4 illustrates an isometric view of an embodiment of a cuttingelement.

FIG. 5 illustrates an end view of an embodiment of a cutting element.

FIG. 6 illustrates an isometric cross-sectional view of an embodiment ofa cutting element.

FIG. 7 illustrates an end view of another embodiment of a cuttingelement, which may be used with the atherectomy catheter of FIG. 1.

FIGS. 8 and 8A illustrate an isometric view of the raised elements ofthe cutting element of FIG. 7.

FIG. 9 illustrates an isometric side view of a portion of theatherectomy catheter illustrated in FIG. 1 with another embodiment of acutting element in a working position.

FIG. 10 illustrates an isometric view of the cutting element illustratedin FIG. 9.

FIG. 11 illustrates an isometric view of a further embodiment of acutting element suitable for use with the atherectomy catheterillustrated in FIG. 1.

FIG. 12 illustrates an isometric view of one embodiment of a subassemblyused to produce the cutting element illustrated in FIG. 11.

FIGS. 13A, 13B, 14A, 14B, 15A and 15B illustrate isometric views ofother embodiments of cutters and cutter subassemblies suitable for usewith the atherectomy catheter illustrated in FIG. 1.

FIGS. 16A and 16B illustrate an isometric view of further embodiments ofa cutter and a subassembly suitable for use with the atherectomycatheter illustrated in FIG. 1.

FIG. 17 illustrates an isometric view of another embodiment of asubassembly used to produce the cutting element illustrated in FIG. 11.

FIGS. 18A, 18B and 18C illustrate schematic views of methods of usingcatheters having embodiments of cutting elements in a human body.

DETAILED DESCRIPTION

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; and a cutting element coupled to the rotatable shaft forrotating the shaft about a longitudinal axis, the cutting element havinga cup-shaped surface and a cutting edge, the cup-shaped surface beingconfigured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction, andthe cutting element having at least one abrasive surface. In oneembodiment, the cutting edge is a radially outer edge of the cuttingelement. In an embodiment, the catheter comprises a raised elementextending outwardly from the cup-shaped surface of the cutting element.In one embodiment, the cutting edge is a radially outer edge of thecutting element and the raised element is recessed proximally from thecutting edge when viewed along the longitudinal axis.

In an embodiment, the cutting element is movable between a storedposition and a cutting position relative to the opening. In oneembodiment, the cutting element is moved between the stored position andthe cutting position by sliding the cutting element against a camsurface. In an embodiment, a distal portion of the catheter relative toa proximal portion is deflected by sliding the cutting element againstthe cam surface.

In embodiments of the invention, the abrasive surface is flush,recessed, or elevated in relation to adjacent non-abrasive cuttingelement surfaces. In an embodiment of the invention, the cutting elementhas a major diameter D in the range of 0.030 to 0.100″ (0.076 to 0.25cm). In one embodiment, the cutting element has a major diameter D of0.061″ (0.15 cm). In an embodiment, the cutting element comprises oneabrasive surface, and in another embodiment the cutting elementcomprises two or more abrasive surfaces. The two or more abrasivesurfaces can comprise at least two surfaces having different abrasiveproperties. In one embodiment, the abrasive surface is comprised ofabrasive material that has been attached to the cutting element. Theabrasive material may comprise diamond plate. In one embodiment, theabrasive material has a particle size of 10 to 800 microns. In oneembodiment, the abrasive surface has been produced without attachingabrasive materials to the cutting element. The abrasive surface can beproduced by knurling, grit blasting, etching, or laser ablation.

In an embodiment of the invention, the abrasive surface is on at least aportion of an outer, major diameter surface of the cutting element. Theouter, major diameter surface may be parallel to a longitudinal axis LAof the cutting element. In one embodiment, the abrasive surface is on aproximal shoulder surface of the cutting element. In an embodiment, oneor more abrasive surfaces are on the entire outer, major diametersurface of the cutting element. In an embodiment of the invention, theabrasive surface is on at least the cup-shaped surface. In anotherembodiment, the abrasive surface is on the raised element. In anotherembodiment, the cutting element comprises two or more abrasive surfaceshaving different abrasive properties and the at least two surfaceshaving different abrasive properties are both on a portion of an outer,major diameter surface of the cutting element.

The invention also provides a method of removing material from a bodylumen, the method comprising: providing an atherectomy catheter, placingthe catheter in the body lumen; and moving the catheter in the bodylumen to contact the cutting element with the material in the bodylumen. In one embodiment, the catheter is moved in a distal direction tocontact the cutting edge with the material in the body lumen. In anotherembodiment, the catheter is moved in a proximal direction to contact theabrasive surface with the material in the body lumen. In an embodiment,the abrasive surface is on a proximal shoulder surface of the cuttingelement. In an embodiment, the catheter is placed in the body lumen withthe cutting element in the stored position and the catheter is moved tocontact the material with the cutting element in a cutting position.

Referring to FIGS. 1 to 4, an atherectomy catheter 2 is shown which hasa cutting element 4, which is used to cut material from a blood flowlumen such as a blood vessel. The cutting element 4 is movable between astored position (FIG. 2) and a cutting position (FIG. 3) relative to anopening 6 in a body 8 of the catheter 2. The cutting element 4 movesoutwardly relative to the opening 6 so that a portion of the element 4extends outwardly from the body 8 through the opening 6. In oneembodiment the cutting element 4 may be positioned relative to the body8 and opening 6 so that less than 90 degrees of the cutting element 4 isexposed to cut tissue. In other embodiments more of the cutting element4 may be exposed without departing from numerous aspects of theinvention.

Distal end of catheter 2 is positioned near a treatment site of a vesselwith cutting element 4 in the stored position. Then catheter 2 is moveddistally through the vessel with the cutting element 4 in the working orcutting position as described in further detail below. As the catheter 2moves through the blood vessel with the cutting element 4 in the workingor cutting position the tissue material is cut by the cutting element 4and is directed into a tissue chamber 12 positioned distal to thecutting element 4. The tissue chamber 12 may be somewhat elongated toaccommodate the tissue which has been cut.

To expose cutting element 4 through opening 6 cutting element 4 is movedproximally from the stored position so that a cam surface 14 on thecutting element 4 engages a ramp 16 on the body 8 of the catheter 2. Theinteraction between the cam surface 14 and the ramp 16 causes thecutting element 4 to move to the cutting position and also causes a tip18 to deflect which tends to move the cutting element 4 toward thetissue to be cut.

The cutting element 4 is coupled to a shaft 20 that extends through alumen 21 in the catheter 2. Catheter 2 is coupled to exemplary cutterdriver 5. Cutter driver 5 is comprised of motor 11, power source 15 (forexample one or more batteries), microswitch (not shown), housing 17(upper half of housing is removed as shown), lever 13 and connectionassembly (not shown) for connecting shaft 20 to driver motor 11. Cutterdriver 5 can act as a handle for the user to manipulate catheter 2.Lever 13, when actuated to close a microswitch, electrically connectspower source 15 to motor 11 thereby causing rotation of cutting element4. The cutting element 4 is rotated about a longitudinal axis LA whenthe shaft 20 rotates. The cutting element 4 is rotated about 1 to160,000 rpm but may be rotated at any other suitable speed dependingupon the particular application. Further description of catheterssimilar to catheter 2 are found in U.S. patent application Ser. No.10/027,418 (published as US 2002/0077642 A1) to Patel et al., entitled“Debulking Catheter”, the contents of which are incorporated byreference herein.

Referring to FIG. 5, the cutting element 4 is shown when viewed alongthe longitudinal axis LA. The term “along the longitudinal axis” as usedherein shall mean for example the view of FIG. 5 that shows the distalend of the cutting element 4 when viewed in the direction of thelongitudinal axis and/or the axis of rotation. The cutting element 4 hasa cutting edge 22 that may be a continuous, uninterrupted,circular-shaped edge although it may also include ridges, teeth,serrations or other features without departing from the scope of theinvention. The cutting edge 22 may be at a radially outer edge 23 of thecutting element 4 when the cutting element 4 is in the cutting position.

The cutting element 4 has a cup-shaped surface 24, which directs thetissue cut by the cutting edge 22 into the tissue chamber 12. Thecup-shaped surface 24 may be a smooth and continuous surface free ofthroughholes, teeth, fins or other features, which disrupt the smoothnature of the surface 24 for at least half the distance from thelongitudinal axis LA to the outer radius at the cutting edge 22. Thecup-shaped surface 24 may also be free of any such features throughoutan area of at least 300 degrees relative to the longitudinal axis LA.

Referring to FIGS. 4 to 6, one or more raised elements 26 extendoutwardly from the cup-shaped surface 24 with FIG. 5 showing two raisedelements 26. The raised element 26 is a small wedge of material thatrises relatively abruptly from the cup-shaped surface 24. The raisedelement 26 has a first wall 30 and a second wall 32 that both extendradially and form an angle of about 20 degrees therebetween so that thetwo raised elements 26 together occupy an area of about 40 degrees andaltogether may be less than 60 degrees. A third wall 34 extends betweenthe radially inner portion of the first and second walls 30, 32. Theraised element 26 helps to break up hard tissue and plaque by applying arelatively blunt force to the hard tissue or plaque since cutting suchtissue with the cutting edge 22 is often not effective.

The raised elements 26 altogether occupy a relative small part of thecup-shaped surface 24. The raised elements 26 together may occupy lessthan 5% of a surface area of the cutting element 4. The term “surfacearea of the cutting element” as used herein shall mean the surface areawhich is radially inward from the outer or cutting edge 22 and isexposed when viewed along the longitudinal axis LA. Stated another way,at least 95% of the surface area of the cutting element is a smoothcup-shaped surface when viewed along the longitudinal axis. By sizingand positioning the raised element 26 in this manner, the raised element26 does not interfere with the ability of the cutting element 4 to cutand re-direct tissue into the tissue chamber while still providing theability to break up hard tissue and plaque with the raised element 26.

The raised element 26 may be recessed from the cutting edge 22longitudinally and/or radially. The raised element 26 may be recessedlongitudinally from the cutting edge 0.0010 to 0.0020 inch (0.0025 to0.0051 cm) and may be about 0.0015 inch (0.0038 cm). The raised element26 may be recessed radially from the cutting edge 22 by about the sameamount. A distal wall 38 of the cutting element 4 forms a flat surface40, which is perpendicular to the longitudinal axis LA so that theentire surface is recessed the same distance from the cutting edge. Thedistal wall 38 may take any other shape, such as a curved shape, or maybe tilted, inclined or beveled as now described.

Referring to FIGS. 7 and 8, another cutting element 4A is shown whereinthe same or similar reference numbers refer to the same or similarstructure and all discussion concerning the same or similar features ofthe cutting element 4 are equally applicable here. The cutting element4A has a cutting edge 22A that may be a continuous, uninterrupted,circular-shaped edge although it may also include ridges, teeth,serrations or other features without departing from the scope of theinvention. The cutting edge 22A may be at a radially outer edge 23A ofthe cutting element 4A when the cutting element 4A is in the cuttingposition. The cutting element 4A has a cup-shaped surface 24A thatdirects the tissue cut by the cutting edge 22A into the tissue chamber12 (see FIG. 2). The cup-shaped surface 24A may be a substantiallysmooth and continuous surface as described above in connection with thecutting element 4.

One or more raised elements 26A extend outwardly from the cup-shapedsurface 24A. FIG. 8 shows four raised elements 26A but may include anynumber such as 2, 3, 4, 6 or 8 raised elements. The raised element 26Ais a small wedge of material that rises relatively abruptly from thecup-shaped surface 24A. The raised element 26A has a first wall 30A anda second wall 32A which both extend radially and form an angle of about1 to 30 degrees therebetween so that the four raised elements 26Atogether occupy an area of about 4 to 60 degrees and altogether may beless than 60 degrees altogether. A third wall 34A extends between theradially inner portion of the first and second walls 30A, 32A. Theraised elements 26A may occupy a relative small part of the cup-shapedsurface 24A and may be recessed from the cutting edge 22A in the mannerdescribed above in connection with the cutting element 4.

A distal wall 38A of the cutting element 4A has a surface 40A that formsan angle of about 30 to 90 degrees with respect to the longitudinal axisLA. The entire surface 40A may still be somewhat close to but recessedfrom the cutting edge 22A so that the entire surface 40A is 0.0010 to0.0050 inch (0.0025 to 0.013 cm) from the cutting edge. An edge 50formed at the intersection of wall 30A and distal wall 38A is closer tothe cutting edge 22A than an edge 52 formed at the intersection of wall32A and distal wall 38A. The cutting element 4A may be rotated in eitherdirection so that the raised edge 50 may be the leading or trailingedge. The raised edge may be 0.0010 to 0.0020 inch from the cuttingedge. The raised elements 26A may all be formed in the same manner ormay be different from one another. For example, some of the elements 26Acould be angled in different directions so that two of the elements havethe raised edge 50 as the leading edge and two of the elements 26A havethe raised edge 50 as the trailing edge. The raised elements 26A mayalso subtend different angles, be of different heights or may havedifferent radial lengths without departing from various aspects of thepresent invention.

Use of the catheter 2 is now described in connection with the cuttingelement 4 but is equally applicable to use of the catheter 2 with thecutting element 4A. The catheter 2 is introduced into the patient in aconventional manner using a guidewire (not shown) or the like. Thecatheter 2 is advanced over the guidewire with the cutting element inthe stored position of FIG. 2 until the catheter is positioned at thelocation where material is to be removed. The cutting element 4 is thenmoved proximally so that the ramp 16 and cam surface 14 engage to movethe cutting element 4 to the cutting position of FIG. 3 and to deflectthe tip of the catheter 2 to move the cutting element 4 toward thetissue to be cut. The cutting element 4 is rotated about longitudinalaxis LA and catheter 2 is then moved distally through the vessel so thatthe cutting element 4 cuts tissue. The tissue, which has been cut, isdirected into the tissue chamber 12.

FIGS. 9 to 17 illustrate further embodiments of cutting elements wellsuited to cut and remove from a blood vessel both relatively soft tissueand relatively hard tissue. Any of cutting elements 90, 100, 130, 140,150 a, 150 b, 160 may be substituted in place of cutting element 4, 4Aof catheter 2. In one example FIG. 9 illustrates cutting element 90assembled into catheter 2, with cutting element 90 exposed throughwindow 6 in a working or cutting position. In FIGS. 9, 10, 11, 13A, 14A,15A, 15B, 16A and 17 abrasive surfaces 92, 102, 102′, 132, 142, 152 a,152 b, 162 a, 162 b are schematically illustrated by means ofnot-to-scale cross hatching. In various embodiments abrasive surfacesare flush with, elevated in relation to, or recessed in relation toadjacent non-abrasive cutting element surfaces.

Cutting elements 90, 100, 130, 140, 150 a, 150 b, 160 are comprised ofcutting blade 22, abrasive surface 92, 102, 102′, 132, 142, 152 a, 152b, 162 a, 162 b, cutter blank 96, 106, 106′, 136, 146, 156 a, 156 b,166, and may be comprised of abrasive materials 94, 104, 104′, 134, 144,154 a, 154 b, 164 a, 164 b. Cutting element major diameter D (see, forexample, FIG. 10) is contemplated to be in the range of 0.030″ to 0.100″ (0.076 to 0.25 cm). In one embodiment, cutting element majordiameter is 0.061″ (0.15 cm). In other embodiments cutting element majordiameter is 0.035″, 0.040″, 0.043″, 0.050″, 0.055″, 0.065″, 0.069″,0.075″, 0.080″ or 0.090″ (0.089 cm, 0.10 cm, 0.11 cm, 0.13 cm, 0.14 cm,0.17 cm, 0.18 cm, 0.19 cm, 0.20 cm, or 0.23 cm). While Cutting element90, 100, 130, 140, 150 a, 150 b, 160 major diameter D (for example, seeFIG. 10) is generally illustrated as comprised of a cylinder havingparallel sides, it is contemplated that the abrasive surface in thevicinity of the major diameter may be concave towards axis LA-LA, convextowards axis LA-LA, or may have other shapes.

Cutting blade 22 may be comprised of hard, tough, abrasion resistantmaterials such as steel, tungsten carbide, tungsten carbide loaded with5% to 20% nickel, silicon carbide, titanium nitride, or other materialsand may be produced by processes comprised of heat treating, ionimplantation, grinding, honing, sharpening, Electrostatic DischargeMachining (EDM) and other processes. In one embodiment cutting blade 22is comprised of tungsten carbide loaded with 15% nickel. Cutter blank96, 106, 106′, 136, 146, 156 a, 156 b, 166 may be comprised of hardenedsteel, stainless steel, titanium and its alloys, or other materials andmay be comprised of one or more recessed or reduced diameter (ascompared to cutting element major diameter D —see for example FIG. 10)regions 107, 137, 147, 167 a, 167 b into which abrasive materials may besecured. In one embodiment the cutter blank is comprised of fullhardened #465 stainless steel.

Abrasive materials 94, 104, 104′, 134, 144, 154 a, 154 b, 164 a, 164 bmay be comprised of hard, particulate materials such as diamond, siliconcarbide, aluminum oxide, tungsten carbide, metal, hardened steel orother materials, having a range of particle sizes and may be defined bygrit size. In one embodiment the abrasive materials have a particle sizeof 40 microns. In other embodiments abrasive materials having particlesizes of 10, 20, 75, 100, 200, 300, 400, 500, 600, 700 or 800 micronsare contemplated. In some embodiments the abrasive materials have gritsizes ranging from P2000 to P24 or anywhere in between as defined by ISOStandard 6344. In further embodiments the abrasive materials have gritsizes ranging from 1000 to 24 or anywhere in between as defined by theCoated Abrasive Manufacturers Institute (CAMI). In some embodimentsabrasive materials may be attached to cutter blank 96, 106, 106′, 136,146, 156 a, 156 b, 166 by means of adhesive bonding, soldering, brazing,welding, sintering, diffusion bonding, plating, press fit or othermeans. In some embodiments abrasive surface 92, 102, 102′, 132, 142, 152a, 152 b, 162 a, 162 b is formed into cutter blank 96, 106, 106′, 136,146, 156 a, 156 b, 166 without the use of abrasive materials byprocesses such as knurling, grit blasting, etching, laser ablation andother processes. In one embodiment abrasive material 94, 104, 104′, 134,144, 154 a, 154 b, 164 a, 164 b is comprised of diamond plate.

In another embodiment FIG. 17 illustrates an exemplary method forproducing cutting elements 90, 100, 130, 140, 150 a, 150 b, 160. Whilethe method is illustrated in the figure using cutting element 100 as anexample, it is contemplated that the method with minor modification canbe used to produce other cutting elements herein described. In themethod, cutting element 100 is comprised of cutter preform 101, abrasivematerial preform 103 and cutter blank 106′. Cutter preform 101, abrasivematerial preform 103 and cutter blank 106′ are comprised of the samematerials and processes described above for cutting blade 22, abrasivematerials 94, 104, 104′, 134, 144, 154 a, 154 b, 164 a, 164 b and cutterblank 96, 106, 106′, 136, 146, 156 a, 156 b, 166 respectively. Cutterpreform 101 is further comprised of through holes 109 and cutter blank106′ is further comprised of fingers 108 which are slidably receivedwithin through holes 109. Fingers 108 are configured to slide withininner diameter of preform 103.

To assemble cutting element 100 using the method illustrated in FIG. 17cutter preform 101, abrasive material preform 103 and cutter blank 106′are prefabricated as individual components. Thereafter abrasive materialpreform 103 is slid over fingers 108 and cutter preform 101 is slid overfingers 108 with fingers 108 slidably received in through holes 109,thereby sandwiching abrasive material preform 103 between cutter preform101 and cutter blank 106′. Fingers are next secured to cutter preform101 by means of processes or a combination of processes such as adhesivebonding, soldering, brazing, welding, sintering, diffusion bonding,mechanically deforming the fingers, or other processes. Advantages ofthe assembly method described are that the cutter preform 101, abrasivematerial preform 103 and cutter blank 106′ can be comprised of differentmaterials, and can be processed by different methods. Also by using themethod, cutting elements such as cutting element 100 can be assembledfrom relatively inexpensive components.

One or more surfaces of cutting element 90, 100, 130, 140, 150 a, 150 b,160 may be comprised of an abrasive surface 92, 102, 102′, 132, 142, 152a, 152 b, 162 a, 162 b including but not limited to, if present, theouter diameter, major diameter, minor diameter, concave surface, convexsurface, raised elements, and other surfaces. Exemplary cutters havingvarious configurations of abrasive surfaces are illustrated anddiscussed below.

FIGS. 9 and 10 illustrate cutting element 90 comprised of cutting blade22 and abrasive surface 94 on a portion of major diameter 91 a and onproximal facing shoulder 91 b. When assembled into catheter 2 withcutting element 90 exposed through window 6 in a working or cuttingposition, cutting element 90 can be advanced distally while rotatingabout axis LA-LA to cut soft material by means of blade 22 and can beretracted proximally while rotating about axis LA-LA to cut or abradehard material by means of abrasive surface 94. Cutting element 90 can beused to selectively remove soft material, hard material, or both.

FIG. 11 illustrates cutting element 100 comprised of cutting blade 22and abrasive surface 104 on a portion of major diameter 101 a. Whenassembled into catheter 2 with cutting element 100 exposed throughwindow 6 in a working or cutting position, cutting element 100 can beadvanced distally while rotating about axis LA-LA to cut soft materialby means of blade 22 and can be retracted proximally while rotatingabout axis LA-LA to cut or abrade hard material by means of abrasivesurface 104. Cutting element 100 can be used to selectively remove softmaterial, hard material, or both. FIG. 12 illustrates cutter blank 106.

FIG. 13A illustrates cutting element 130 comprised of cutting blade 22and abrasive surface 134 on all of major diameter 131 a and on proximalfacing shoulder 131 b. When assembled into catheter 2 with cuttingelement 130 exposed through window 6 in a working or cutting position,cutting element 130 can be advanced distally while rotating about axisLA-LA to cut soft material by means of blade 22 and can be retractedproximally while rotating about axis LA-LA to cut or abrade hardmaterial by means of abrasive surface 134. Cutting element 130 can beused to selectively remove soft material, hard material, or both, andcan abrade large amounts of material per pass due to the large surfacearea covered with abrasive material. FIG. 13B illustrates cutter blank136.

FIG. 14A illustrates cutting element 140 comprised of cutting blade 22and abrasive surface 144 on proximal facing shoulder 141 b. Whenassembled into catheter 2 with cutting element 140 exposed throughwindow 6 in a working or cutting position, cutting element 140 can beadvanced distally while rotating about axis LA-LA to cut soft materialby means of blade 22 and can be retracted proximally while rotatingabout axis LA-LA to cut or abrade hard material by means of abrasivesurface 144. Cutting element 140 can be used to selectively remove softmaterial, hard material, or both, and will abrade less material per passthan cutting element 130 for a given abrasive material grit size,surface speed, and exposure through window 6. FIG. 14B illustratescutter blank 146.

FIG. 15A illustrates cutting element 150 a comprised of cutting blade22, optional raised elements 26, 26A and abrasive surface 154 a oncup-shaped surface 24 and optionally on any or all surfaces of raisedelements 26, 26A. When assembled into catheter 2 with cutting element150 a exposed through window 6 in a working or cutting position, cuttingelement 150 a can be advanced distally while rotating about axis LA-LAto cut soft material by means of blade 22 and also cut or abrade hardmaterial by means of abrasive surface 154 a and (optional) raisedelements 26, 26A. Material so cut by cutting element 150 a will bedirected into tissue chamber 12 by means of cup-shaped surface 24 ofcutting element 150 a.

FIG. 15B illustrates cutting element 150 b comprised of cutting blade22, optional raised elements 26, 26A and abrasive surface 154 b oncup-shaped surface 24, optionally on any or all surfaces of raisedelements 26, 26A, at least a portion of major diameter 151 a and onproximal facing shoulder 151 b. When assembled into catheter 2 withcutting element 150 b exposed through window 6 in a working or cuttingposition, cutting element 150 b can be advanced distally while rotatingabout axis LA-LA to cut soft material by means of blade 22 and also cutor abrade hard material by means of abrasive surfaces 154 b and(optional) raised elements 26, 26A, and can be retracted proximallywhile rotating about axis LA-LA to cut or abrade hard material by meansof abrasive surface 154 a on shoulder 151 b and major diameter 151 a.Material cut by distal advancement of cutting element 150 b will bedirected into tissue chamber 12 by means of cup-shaped surface 24 ofcutting element 150 b.

FIG. 16A illustrates cutting element 160 comprised of cutting blade 22and abrasive surfaces 164 a, 164 b on a portion of major diameter 161 a.When assembled into catheter 2 with cutting element 160 exposed throughwindow 6 in a working or cutting position, cutting element 160 can beadvanced distally while rotating about axis LA-LA to cut soft materialby means of blade 22 and can be retracted proximally while rotatingabout axis LA-LA to cut or abrade hard material by means of abrasivesurfaces 164 a, 164 b. In one embodiment abrasive surface 164 a is moreaggressive than abrasive surface 164 b, and will quickly abrade largematerial deposits LD that extend a large distance from the luminalsurface LS of a vessel V, while abrasive surface 164 b will slowlyabrade small material deposits SD that extend a short distance from theluminal surface LS of a vessel V. Also, in this embodiment, abrasivesurface 164 b will cause less trauma to luminal surface LS of vessel Vthan abrasive surface 164 a because abrasive surface 164 b is lessaggressive than abrasive surface 164 a. Further, in some embodiments,abrasive surface 164 b may be used to polish the luminal surface(s) ofdeposits in the vessel. FIG. 16B illustrates cutter blank 166.

In some embodiments cutting element 160 may be comprised of more thantwo surfaces of different abrasive characteristics on major diameter 161a. For example, cutting element 160 may be comprised of 3, 4, 5, 6, ormore surfaces of different abrasive characteristics. In one embodimentcutting element 160 is comprised of an abrasive surface thatcontinuously changes from a less aggressive surface to a more aggressivesurface on major diameter 161 a. In some embodiments the continuouslychanging abrasive surface is least aggressive at the surface's distalmost extent, or most aggressive at the surface's distal most extent.

In another embodiment, catheters 2 comprised of cutting elements 90,100, 130, 140, 150 a, 150 b, 160 having both cutting blades and abrasivesurfaces may be further comprised of cutter driver 5 capable of rotatingthe cutting element at two or more speeds. In one embodiment a cutterdriver 5 is contemplated that rotates the cutting element at a firstspeed when cutting with cutting blade 22 and rotates the cutting elementat a second speed when abrading with abrasive surface 92, 102, 102′,132, 142, 152 a, 152 b, 162 a, 162 b. In some embodiments the firstspeed is chosen such that cutter surface speed is effective for cuttingsoft material and the second speed is chosen such that abrasive surfacespeed is effective for quickly abrading hard material. In otherembodiments cutter driver 5 rotates cutting element 90, 100, 130, 140,150 a, 150 b, 160 at variable speeds. Cutting element first and secondspeeds are contemplated to be in the range of 1,000 to 160,000 RPM. Inone embodiment, cutting element first and second speeds are 8,000 RPM.In other embodiments cutting element first and second speeds are 1,000RPM, 2,000 RPM, 4,000 RPM, 16,000 RPM, 32,000 RPM, 64,000 RPM, 80,000RPM or 120,000 RPM. In some embodiments, cutting element second speed iscontemplated to be in the range of 1,000 to 100,000 RPM greater thancutting element first speed. In one embodiment, cutting element secondspeed is 50,000 RPM greater than cutting element first speed. In otherembodiments cutting element second speed is 5,000 RPM, 10,000 RPM,20,000 RPM, 40,000 RPM or 75,000 RPM greater than cutting element firstspeed. In still further embodiments cutting element surface speedagainst the vessel wall material is contemplated to be in the range of50 to 4,150 surface feet per minute (SFM). In one embodiment, cuttingelement surface speed is 1,500 SFM. In other embodiments cutting elementsurface speed is 100 SFM, 200 SFM, 800 SFM, 2,000 SFM or 3,000 SFM. Inother embodiments cutting element surface speeds at cutting elementsecond speed (RPM) are contemplated to be in the range of 100 to 3,000SFM greater than cutting element surface speed at cutting element firstspeed (RPM). In one embodiment, cutting element second surface speed is2,000 SFM greater than cutting element first surface speed. In otherembodiments cutting element second surface speed is 200 SFM, 500 SFM,1,000 SFM or 2,500 SFM greater than cutting element first surface speed.Cutting element variable speed ranges, both RPM and SFM, arecontemplated to vary within the same ranges as cutting element first andsecond speeds.

Cutter drivers 5 capable of rotating cutting element 90, 100, 130, 140,150 a, 150 b, 160 at a first speed and at a second speed may becomprised of a two position microswitch that electrically connects onebattery to motor 11 causing rotation of motor 11 at a first speed andthat electrically connects two batteries to motor 11 causing rotation ofmotor 11 at a second speed, or other means. Cutter drivers 5 capable ofrotating cutting element 90, 100, 130, 140, 150 a, 150 b, 160 at avariable speed may be comprised of a variable resistance microswitchthat electrically connects a variable resistance between battery andmotor 11 causing variable speed rotation of motor 11, or other means.

Exemplary methods of using an atherectomy catheter comprised of cuttingelements having both cutting blades and abrasive surfaces to cut andremove material from a body of a patient are now described.

Using techniques known in the art, a guidewire GW is percutaneouslyinserted into a patient's body and advanced to a region of interest in apatient's blood vessel V. Using imaging techniques such as fluoroscopy adiseased portion of the vessel is identified and an atherectomy catheter(such as catheter 2) comprised of a cutting element CE, for examplecutting element 90, 100, 130, 140, 150 b, 160, having appropriatecharacteristics for treatment site T is chosen. With reference to FIG.18A, catheter 2 is advanced over the guidewire to the treatment sitewith the cutting element in a stored position. Using imaging techniquessuch as fluoroscopy the cutting element is positioned at a desiredlocation relative to (in some methods proximal to) the treatment site.

Catheter shaft 20 is held stationary, the cutting element CE ismanipulated into a cutting position (i.e. exposed through window 6) andcutting element rotation is activated using lever 13. Catheter shaft 20is advanced distally causing cutter blade 22 to cut material M fromluminal surface LS of vessel V. Cup shaped surface 24 directs cutfragments of material M through thru window 6 into collection chamber 12(FIG. 18B). Catheter shaft 20 is retracted proximally and abrasivesurface AS, for example abrasive surface 92, 102, 102′, 132, 142, 152 a,152 b, 162 a, 162 b, abrades material M from luminal surface LS ofvessel V (FIG. 18C). Rotation of the cutting element is stopped, thecutting element is returned to the storage position and catheter 2 iswithdrawn from the treatment site T.

In some methods the cutting element is rotated at a first speed whencutting material M from luminal surface LS of vessel V and the cuttingelement is rotated at a second speed when abrading material M fromluminal surface LS of vessel V. In some methods the second speed isgreater than the first speed.

In another method guidewire GW is percutaneously inserted into apatient's body and advanced to a region of interest in a patient's bloodvessel V. Using imaging techniques such as fluoroscopy a diseasedportion of the vessel is identified and an atherectomy catheter (such ascatheter 2) comprised of a cutting element CE, for example cuttingelement 150 b having appropriate characteristics for treatment site T ischosen. With reference to FIG. 18A, catheter 2 is advanced over theguidewire to the treatment site with the cutting element in a storedposition. Using imaging techniques such as fluoroscopy the cuttingelement is positioned at a desired location relative to (in some methodsproximal to) the treatment site.

Catheter shaft 20 is held stationary, the cutting element is manipulatedinto a cutting position (i.e. exposed through window 6) and cuttingelement rotation is activated using lever 13. Catheter shaft 20 isadvanced distally causing cutter blade 22 to cut and abrasive surface ASto abrade material M from luminal surface LS of vessel V. Cup shapedsurface 24 directs cut and abraded fragments of material M through thruwindow 6 into collection chamber 12 (FIG. 18B). Catheter shaft 20 isretracted proximally and abrasive surface AS, for example abrasivesurface 152 b, abrades material M from luminal surface LS of vessel V(FIG. 18C). Rotation of the cutting element is stopped, the cuttingelement is returned to the storage position and catheter 2 is withdrawnfrom the treatment site T.

In some methods the cutting element is rotated at a first speed whencutting material M from luminal surface LS of vessel V and the cuttingelement is rotated at a second speed when abrading material M fromluminal surface LS of vessel V. In some methods the second speed isgreater than the first speed.

In yet another method guidewire GW is percutaneously inserted into apatient's body and advanced to a region of interest in a patient's bloodvessel V. Using imaging techniques such as fluoroscopy a diseasedportion of the vessel is identified and an atherectomy catheter (such ascatheter 2) comprised of a cutting element CE, for example cuttingelement 150 a, having appropriate characteristics for the treatment siteT is chosen. With reference to FIG. 18A, catheter 2 is advanced over theguidewire to the treatment site with the cutting element in a storedposition. Using imaging techniques such as fluoroscopy the cuttingelement is positioned at a desired location relative to (in some methodsproximal to) the treatment site.

Catheter shaft 20 is held stationary, the cutting element is manipulatedinto a cutting position (i.e. exposed through window 6) and cuttingelement rotation is activated using lever 13. Catheter shaft 20 isadvanced distally causing cutter blade 22 to cut and abrasive surface ASto abrade material M from luminal surface LS of vessel V. Cup shapedsurface 24 directs cut and abraded fragments of material M through thruwindow 6 into collection chamber 12 (FIG. 18B). Rotation of the cuttingelement is stopped, the cutting element is returned to the storageposition and catheter 2 is withdrawn from the treatment site T.

In some methods the cutting element is rotated at a first speed whencutting material M from luminal surface LS of vessel V and the cuttingelement is rotated at a second speed when abrading material M fromluminal surface LS of vessel V. In some methods the second speed isgreater than the first speed.

In addition to use in blood vessels the invention is envisioned to beuseful for removal of blockages in other blood flow lumens such asnatural or artificial grafts, stent-grafts, anastomotic sites, fistulae,or other blood flow lumens.

The present invention has been described in connection with preferredembodiments but may, of course, be practiced while departing from theabove described embodiments. For example, three or more raised elementsmay be provided or cutting edge may be serrated without departing fromnumerous aspects of the present invention.

The above description and the drawings are provided for the purpose ofdescribing embodiments of the invention and are not intended to limitthe scope of the invention in any way. It will be apparent to thoseskilled in the art that various modifications and variations can be madewithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. Further, while choices formaterials and configurations may have been described above with respectto certain embodiments, one of ordinary skill in the art will understandthat the materials and configurations described are applicable acrossthe embodiments.

1. An atherectomy catheter, comprising: a body having an opening; arotatable shaft coupled to the body; a tissue collection chamber coupledto the body and positioned distal to the cutting element; and a cuttingelement coupled to the rotatable shaft for rotating the shaft about alongitudinal axis, the cutting element having a cup-shaped surface and acutting edge, the cup-shaped surface being configured to re-directtissue cut by the cutting edge in a distal direction when the cup-shapedsurface moves in the distal direction, and the cutting element having atleast one abrasive surface.
 2. The catheter of claim 1, wherein thecutting edge is a radially outer edge of the cutting element.
 3. Thecatheter of claim 1, wherein the catheter comprises a raised elementextending outwardly from the cup-shaped surface of the cutting element.4. The catheter of claim 3, wherein: the cutting edge is a radiallyouter edge of the cutting element; and the raised element is recessedproximally from the cutting edge when viewed along the longitudinalaxis.
 5. The catheter of claim 1, wherein the cutting element is movablebetween a stored position and a cutting position relative to theopening.
 6. The catheter of claim 5, wherein the cutting element ismoved between the stored position and the cutting position by slidingthe cutting element against a cam surface.
 7. The catheter of claim 6,wherein a distal portion of the catheter relative to a proximal portionis deflected by sliding the cutting element against the cam surface. 8.The catheter of claim 1, wherein the abrasive surface is flush inrelation to adjacent non-abrasive cutting element surfaces.
 9. Thecatheter of claim 1, wherein the abrasive surface is recessed inrelation to adjacent non-abrasive cutting element surfaces.
 10. Thecatheter of claim 1, wherein the abrasive surface is elevated inrelation to adjacent non-abrasive cutting element surfaces.
 11. Thecatheter of claim 1, wherein the cutting element has a major diameter Din the range of 0.030 to 0.100″ (0.076 to 0.25 cm).
 12. The catheter ofclaim 1, wherein the cutting element has a major diameter D of 0.061″(0.15 cm).
 13. The catheter of claim 1, wherein the cutting elementcomprises one abrasive surface.
 14. The catheter of claim 1, wherein thecutting element comprises two or more abrasive surfaces.
 15. Thecatheter of claim 14, wherein the two or more abrasive surfaces compriseat least two surfaces having different abrasive properties.
 16. Thecatheter of claim 1, wherein the abrasive surface is comprised ofabrasive material that has been attached to the cutting element.
 17. Thecatheter of claim 16, wherein the abrasive material comprises diamondplate.
 18. The catheter of claim 16, wherein the abrasive material has aparticle size of 10 to 800 microns.
 19. The catheter of claim 1, whereinthe abrasive surface has been produced without attaching abrasivematerials to the cutting element.
 20. The catheter of claim 19, whereinthe abrasive surface has been produced by knurling, grit blasting,etching, or laser ablation.
 21. The catheter of claim 1, wherein theabrasive surface is on at least a portion of an outer, major diametersurface of the cutting element.
 22. The catheter of claim 21, whereinthe abrasive surface on the outer, major diameter surface is parallel toa longitudinal axis LA of the cutting element.
 23. The catheter of claim1, wherein the abrasive surface is on a proximal shoulder surface of thecutting element.
 24. The catheter of claim 21, wherein the abrasivesurface is on a proximal shoulder surface of the cutting element. 25.The catheter of claim 21, wherein one or more abrasive surfaces are onthe entire outer, major diameter surface of the cutting element.
 26. Thecatheter of claim 25, wherein the abrasive surface is on a proximalshoulder surface of the cutting element.
 27. The catheter of claim 1,wherein the abrasive surface is on at least the cup-shaped surface. 28.The catheter of claim 2, wherein the abrasive surface is on the raisedelement.
 29. The catheter of claim 28, wherein the abrasive surface ison the cup-shaped surface.
 30. The catheter of claim 27, wherein theabrasive surface is on at least a portion of an outer, major diametersurface of the cutting element.
 31. The catheter of claim 30, whereinthe abrasive surface is on a proximal shoulder surface of the cuttingelement.
 32. The catheter of claim 31, wherein the abrasive surface ison the raised element.
 33. The catheter of claim 15, wherein the atleast two surfaces having different abrasive properties are both on aportion of an outer, major diameter surface of the cutting element. 34.A method of removing material from a body lumen, the method comprising:providing an atherectomy catheter, the atherectomy catheter comprising:a body having an opening; a rotatable shaft coupled to the body; atissue collection chamber coupled to the body and positioned distal tothe cutting element; and a cutting element coupled to the rotatableshaft for rotating the shaft about a longitudinal axis, the cuttingelement having a cup-shaped surface and a cutting edge, the cup-shapedsurface being configured to re-direct tissue cut by the cutting edge ina distal direction when the cup-shaped surface moves in the distaldirection, and the cutting element having at least one abrasive surface;placing the catheter in the body lumen; and moving the catheter in thebody lumen to contact the cutting element with the material in the bodylumen.
 35. The method of claim 34, wherein the catheter is moved in adistal direction to contact the cutting edge with the material in thebody lumen.
 36. The method of claim 35, wherein the catheter is moved ina proximal direction to contact the abrasive surface with the materialin the body lumen.
 37. The method of claim 36, wherein the abrasivesurface is on a proximal shoulder surface of the cutting element. 38.The method of claim 34, wherein the catheter is placed in the body lumenwith the cutting element in the stored position and the catheter ismoved to contact the material with the cutting element in a cuttingposition.